Ubiquitin networks in cancer.

Conjugation of ubiquitin to cellular proteins has emerged as a post-translational modification, which affects major cellular processes, including cell cycle, proliferation and apoptosis. The ubiquitin-mediated signaling is frequently altered in cancer cells, with several tumor suppressors and oncogenes representing enzymes of the ubiquitin conjugation and deconjugation pathways. Recently, ubiquitination has been involved into selective degradation of both proteins and mitochondria by autophagy. Studying this novel role of ubiquitin can shed light on autophagy as a tumor suppressor mechanism as well as provide insights into the role of autophagy in survival of tumor cells, thus aiding the design of better cancer therapies.